President Barack Obama has said sorry to California's attorney general after describing her as the "best-looking" prosecutor in the country.

His slip-of-the-tongue came after he lauded Kamala Harris as brilliant, dedicated and tough as he introduced her at a Democratic Party fundraiser.

He said: "She is exactly what you'd want in anybody who is administering the law, and making sure that everybody is getting a fair shake. She also happens to be by far the best-looking attorney general in the country."

Ms Harris with actor Sean Penn at a Haiti fundraiser

On a day that saw Mr Obama's wife, Michelle, also forced to backtrack during an interview in which she accidentally termed herself a "busy, single mother," the White House said Mr Obama telephoned Ms Harris to say sorry.

"The president did speak with Attorney General Harris last night after he came back from his trip, and he called her to apologise for the distraction created by his comments," spokesman Jay Carney told reporters.

"They are old friends and good friends, and he did not want in any way to diminish the attorney general's professional accomplishments."

Mr Carney noted that Mr Obama's "best-looking" remark about Ms Harris came after the series of comments that praised her effectiveness as a prosecutor, but critics slammed the president's conduct.

Michelle Obama made her own gaffe during an interview in Vermont

New York Magazine's Jonathan Chait said: "It's not a compliment. And for a president who has become a cultural model for many of his supporters in so many other ways, the example he's setting here is disgraceful."

The first lady, meanwhile, also ran into trouble when speaking to a CBS News affiliate in Vermont about the strains of being a working parent.

"Believe me, as a busy single mother," she said, before correcting herself.

"I shouldn't say single. As a busy mother. Sometimes, you know, when you've got a husband who is president, it can feel a little single. But he's there."